<template>
    <div class="nav-bar" :class="{'is-fixed':isFixed}">
        <div class="container">
            <div class="pro-title">{{title}}</div>
            <div class="pro-param">
                <a href="javascript:;">概述</a><span>|</span>
                <a href="javascript:;">参数</a><span>|</span>
                <a href="javascript:;">用户评价</a>
                <slot name="buy"></slot>
            </div>
        </div>
    </div>
</template>
<script>
export default {
    name:'nav-bar',
    props:{
      title:String,
    },
    data(){
        return{
            isFixed:false,
        }
    },
    mounted(){
        window.addEventListener('scroll',this.initHeight);
    },
    methods:{
        initHeight(){
            let scrollTop = window.pageYOffset || window.document.scrollTop || window.body.scrollTop;
            //谷歌浏览器用 document.documentElement.scrollTop，ie浏览器用 document.body.scrollTop 解决兼容问题
            this.isFixed = scrollTop > 152?true:false;
        }
    },
    destroyed(){
        window.removeEventListener('scroll',this.initHeight,false)//false为冒泡
    }
}
</script>
<style lang="scss">
  @import './../assets/scss/config.scss';
  @import './../assets/scss/mixin.scss';
  .nav-bar{
    height:70px;
    line-height:70px;
    border-top:1px solid $colorH;
    background-color:$colorG;
    z-index:10;
    &.is-fixed{
        position: fixed;
        top: 0;
        width: 100%;
        box-shadow: 0 5px 5px $colorE;
    }
    .container{
      @include flex();
      .pro-title{
        font-size:$fontH;
        color:$colorB;
        font-weight:bold;
      }
      .pro-param{
        font-size:$fontJ;
        span{
          margin:0 10px;
        }
        a{
          color:$colorC;
        }
      }
    }
  }
</style>